518 The Journal of Human Resources
I. Introduction
A large literature has established that low birth-weight babies are more likely to suffer various deficits, including lower average educational attainment.
But prior research has not asked how poor child health after birth affects long-term outcomes? We provide a first look at this question using a unique administrative
data set based on public health insurance records from the Canadian province of Manitoba. The data combines information from birth records, hospitalizations, and
ambulatory physician visits with information from other provincial registers about educational outcomes and use of social assistance. The information about health and
outcomes is much more complete, and in many ways more accurate, than what is typically available in survey data. And because Canada has universal public health
insurance, this study sheds light on the consequences of disparities in child health in a setting that abstracts from differences in access to insurance coverage.
We follow 50,000 children and their siblings who were born in Manitoba between 1979 and 1987, until 2006, when they are young adults. We compare siblings with
different childhood health problems conditional on health at birth. We are able to compare the impacts of health problems at different ages, and to examine the con-
sequences of different types of health problems including asthma, major injuries, externalizing mental health conditions, and other major conditions.
Our results suggest that many physical health problems in early life are significant predictors of future adult outcomes. But this is largely because poor health in child-
hood predicts poor health in young adulthood. Short-term health events generally have little long-run impact. Mental health problems are a different story—we find
that diagnoses of attention deficit hyperactivity disorder ADHD or conduct disorder at school entry are significant predictors of future outcomes whether or not future
health problems occur. We conclude that poor health in childhood may be a signifi- cant source of socioeconomic disparities in adulthood.
II. Background
There is a large literature linking low birth weight to lower average scores on a variety of tests of intellectual and social development see for example,
Breslau et al. 1994; Brooks-Gunn, Klebanov, and Duncan 1996; Currie and Hyson 1999. Several recent studies use sibling comparisons to assess the relationship be-
tween low birth weight and future outcomes Conley and Bennett 2000; Johnson and Schoeni 2007; Lawlor et al. 2006; Black, Devereux, and Salvanes 2005; Royer
2005; Currie and Moretti 2007. Oreopoulos et al. 2008 examine the Manitoba data used in this study and, consistent with the other studies, find that siblings of
lower birth weight have worse outcomes. They did not, however, have any data on health after birth.
In fact, very few studies have examined the effect of child health after birth on future outcomes.
1
Case, Fertig, and Paxson 2005 use data from the 1958 British
1. Salm and Schunk 2008 use administrative data from a German city and show that six-year-old children with health problems also have lower test scores, but they are not able to track the children over time.
Currie, Stabile, Manivong, and Roos 519
birth cohort study and show that children who suffered chronic conditions as children had lower educational attainment, wages, and employment probabilities than other
children. Smith 2009 examines the long-term effects of child health using a retrospective
health measure using data from the Panel Study of Income Dynamics PSID. In 1999, the 25–47-year-old adult children of PSID respondents were asked whether
their health when they were younger than 16 was excellent, very good, good, fair, or poor. In models with sibling fixed effects, Smith finds significant negative effects
of poor overall health status in childhood on earnings.
Case and Paxson 2006 treat adult height as an indicator of childhood health, and show that much of the wage premium associated with adult height can be
explained by children’s cognitive test scores. They interpret their results as evidence that early child health affects cognition, which in turn affects earnings.
Our study improves on this literature in several ways. First, we have a continuous measure of health that is taken from medical records and covers the child’s entire
life. This is an improvement over retrospective measures, or the snapshots that are available in the British Cohort Study. Second, we are able to compare children to
their own siblings, in order to control for fixed aspects of family background that may affect both health during childhood and future outcomes.
III. Data
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